What effect does inversion have on the migration of pollutants in the atmosphere?

The influence of inversion on the migration of pollutants in the atmosphere: inversion will reduce the temperature difference between the upper and lower air layers and the convection between them, thus reducing the movement of air. Without the movement of air, pollutants are difficult to diffuse, which makes pollutants in the air exist for a long time and is not conducive to the migration of pollutants.

Inversion phenomenon generally refers to inversion (weather phenomenon). In general, the atmospheric temperature decreases with the increase of altitude, but under some weather conditions, the atmospheric structure above the ground will have an abnormal phenomenon that the temperature increases with the increase of altitude, which is called "inversion" in meteorology, and the atmosphere with inversion phenomenon is called "inversion layer".

Inversion of temperature can inhibit the occurrence of sandstorms to a certain extent, which is also very beneficial to the flight of aircraft. It can also be used in grain planting to improve the yield and quality, but it will also bring significant air pollution in most cases.

In the troposphere, the vertical distribution of temperature generally decreases with the increase of height, and it decreases by about 0.6℃ per 100 meter. However, under certain conditions, the temperature in the troposphere will also increase with the elevation, or the change rate of cooling on the ground is less than 0.6℃/ 100 m, which is called inversion.

Radiation inversion: It often occurs in a clear and cloudless night sky. Due to the strong effective radiation on the ground, the temperature in the near-surface layer drops rapidly, while the temperature in the upper atmosphere drops less, resulting in the inversion phenomenon of upper warming and lower cooling. This inversion is the strongest before dawn and disappears from bottom to top after sunrise. The thickness of radiation inversion can reach tens to hundreds of meters. It may be thousands of meters thick in the polar regions.

Topographic inversion: mainly caused by topography, mainly in basins and valleys. Because of the rapid heat dissipation on the hillside, the cold air sinks to the bottom of the valley along the hillside, and the originally warmer air at the bottom of the valley is pushed up by the cold air, resulting in the inversion of the temperature.

Influencing factors of inversion phenomenon:

1. Geographical location: the phenomenon of subsidence inversion is more likely to occur in mid-latitude areas. At latitude 30, dry air sinks, compresses, and heats itself, with more sunny days and less rain. The temperature after self-heating is higher than that of the lower air, which is more likely to lead to inversion.

2. Time factor: the distribution of inversion layer will change with time. Take the equator as an example. During the summer solstice, the sun shines directly on the Tropic of Cancer, and the mid-latitude area is more prone to inversion.

3. Weather factors: it is partly cloudy at night, and the ground heat dissipates quickly and the temperature drops quickly, which reduces the difference between the ground temperature and the upper air temperature, and reduces the possibility of radiation inversion the next morning. Precipitation weather will reduce the probability of inversion, and foggy weather will increase the probability of inversion.

4. Terrain: When there are many valleys and hills, the cold air stays in the valleys at night and does not pass with the upper hot air flow, which partially meets the conditions for the formation of inversion, which will more easily lead to inversion. In coastal areas, the inversion layer is narrowed by the cold air blowing inland from the sea surface, and then the inversion layer is generated on the coastal ground.

5. Degree of air pollution: The heavier the air pollution, the higher the thickness of inversion layer and the more serious the inversion phenomenon.